Wafer surface contamination control becomes a primary task to improve the yield of wafers for the semiconductor and wafer fabs as well as the manufacturers of other high technologies. During fabricating large size semiconductor wafers, the front opening unified pod (FOUP) is used for storing and transporting the wafers, to separate the large size wafers from the exterior air and to prevent contaminations of the large size wafers.
The load port operates in coordination with FOUP and other microchip fabrication equipments. It functions as a device to carry and open the door of FOUP so that the fabricating equipment can receive large size wafers for fabricating. Since the interior of FOUP becomes partially vacuumed when the door of FOUP is closed, once the door of FOUP is opened by the load port, the exterior atmosphere air may flush into the FOUP to contaminate the large size wafers, and thus reduces the fabrication yield.
Therefore, in order to improve the yield of wafer fabrication, the problems of sudden atmosphere air influx caused by opening the door of FOUP have to be resolved to avoid atmosphere air flows into the interior of FOUP. Hence, the load port is further devised to provide a function of purge, which means that the load port itself can supply clean gas to fill in the interior of FOUP, so that the clean gas inside the FOUP flows outward to exterior atmosphere, and thus prevent the current problem of atmosphere air influx. Based on the designs described above, the bottom of FOUP is configured with an inlet nozzle and an outlet nozzle.
However, the conventional load ports are not provided with purge techniques, and are unable to supply clean gas to fill in the interior of FOUP. Therefore, the present invention provides a purge load port which effectively ensures the cleanness inside the FOUP.
Furthermore, since the load ports are universal equipments, it is required to operate in coordination with various types of FOUPs. Different manufacturers may manufacture various FOUPs with variant design and specifications, which leads to variant interface configurations. For example, some FOUPs are formed with a recess or notch around the rear bottom, and particularly the recess or notch is configured between two inlet nozzles; and some FOUPs is devised flatly around the rear bottom. Accordingly, if the load port is used to purge a specific FOUP, the load port has to recognize the specific FOUP before determining whether to purge or not.